I watched an episode of “Nature” last night on PBS, and it was all about large animals—how they survive, how they feed themselves, what their biggest challenges are, and so on—and it featured the biggest animal of all, the blue whale. Not only is it the largest animal in the world today, but scientists also believe it to be the largest animal that has ever existed. At as much as  100 feet and 220 tons, it dwarfs even the biggest of the dinosaurs.

It is an awesome thing (and I don’t use the word “awesome” casually—ask anybody) to watch this gargantuan beast rise to the surface of the ocean for air and then to return to the depths, the length of its body arcing back into the water with a final flourish of its massive fluke. One can only imagine the breathtaking wonder one would experience to be in the actual presence of this giant of the deep.

I do imagine it regularly, and in a particular context. For the past couple of years I have engaged in the nightly practice of centering prayer. This is an apophatic type of prayer, which means it involves clearing one’s mind in order to experience the presence of God. Centering prayer is silent prayer; one does not put words to requests, supplications, or expressions of praise. Instead, one sits in the silence and seeks to clear one’s mind of thoughts as much as possible in order to “be still, and know that God is God,” to paraphrase the psalmist.

Ay, there’s the rub. I can sit in silence; I can make my body still; but I have great difficulty stilling my thoughts. So what I do is to use imagery. One tenet of centering prayer (and other contemplative practices) is that we encounter God in the depths of our being. So I imagine my depths as the ocean, and I visualize myself floating in the water where it is deep enough to block out sound and light. I try to rest there and let my thoughts pass as though they were ships on the surface of the sea far above.

I don’t know if I came up with this next thing, or if it came to me from another source, but lately I have started imagining a blue whale passing silently by where I am floating. I am always awed by the immensity of this being, and I imagine that the whale is God swimming up from the depths to meet me. This is how I experience the mysterium tremendum, the “tremendous mystery” of the divine presence that Elijah experienced at the mouth of his cave when the “sound of sheer silence” served as prelude to the word of God coming to him. It is the frightening holiness of the presence of God that Moses encountered in the bush that burned but was not consumed.

We sometimes become too familiar with God. We can fall into the habit of thinking of prayer as akin to borrowing a cup of sugar from our next-door neighbor. And God is indeed intimately present with us in all the mundane moments of our lives. But we need also to remember that the Divine is a transcendent mystery possessed of power and glory we cannot begin to fathom. Like a blue whale sliding past us in the silent darkness, multiplied by a million. It is good, I think, to be a little afraid when we approach God. It helps us to maintain a sense of respect and awe, and it guards us against over-familiarity. The fear of God is the beginning of wisdom, and wisdom says, “Take off your shoes (or swim fins, as the case may be), for the place where you are standing (or floating) is holy.” Holy ground. Holy water. Holy presence.